Selective fire converter for semiautomatic firearms



A. F. GAIDOS Feb. 26, 1952- F iled Sept. 27, 1950 5 Sheets-Sheet lINVENTOR. yaponzo 3 emnos fiTTORNEY n v v N T w mm mm mm g? 8 Wm mv n; io fl/YV/Au 2.2%:52.5% QU Ji l I Iii/Z155 @N A. F.. GAIDOS Feb. 26, 1952SELECTIVE FIRE CONVERTER FOR SEMIAUTOMATIC FIREARMS 5 Sheets-Sheet 2Filed Sept. 27, 1950 A. F. GAIDOS Feb. 26, 1952 SELECTIVE FIRE CONVERTERFOR SEMIAUTOMATIC FIREARMS 3 Sheets-Sheet 5 Filed Sept. 27, 1950Patented Feb. 26, 1952 UNITED stares PATENT iOFFlCE JSELECTIVE FIRECONVERTER FOR SEMIAUTOMATIC FIREARMS Alonzo F. Gaidos, Redwood City;Calif. .;.Apiplication September 27, 1950, Serial No. 187,035

' '16 Claims. 1 I I This invention relates. to. a selective-fire. con-.verter which maybe attached-tea. semi-automaticfirearm to provideforsemi-automaticfire or full automtaic fire at themselectionvof themarksman.

. Heretofore, several selective fire converters have-been developed forattachment to the U..S. carbine, caliber-30M1 largequantities of .which-.are-now stored. As originally designed-and-dis- ..closed in HumestonPatent No. 2,308,283,;this Weapon is fired semi-automatically, that is,a pull onthe trigger. fires. a .single round, reloads a .shell in thechamber. and cocksthe firing mechanism. .Tofire a second round, thetriggermust-be re- --leased and again pulled. .Two of the. previouslydeveloped selective .fire. converters .are disclosed in my co-pendingapplications, Serial.No.- 730,2L4, filed October 16, 1947,..and.-Serial.No. 138,766, filed January 16, .1950. The .convertersTdisclosed in theseco-pending. applicationsare-itheonly ones which accomplish thegdesired.result ,without-modifying or remachiningv operating partsof the basicweapon. vThepresent invention .isan

improvement upon the selective'fireconverters disclosed in theseco-pending patent applications.

.-A majorobject of this invention is' to provide a selective fireconverter, having a simplified mechanism whichis easier to install andmaintain. An important object ,ofithe. inventionis ;to provide a.selective .fire, converter? having com- .ponent partswhich may be. moreeconomically manufactured.

' In the attainment of theseobje'cts, oneifeature of the inventionresides in. the. construction of. a sear tripper .which .is'mounted on"the pivot pin l- .for .the hammer and is operated by a sliding ac- .ltuator .barl arranged to be reciprocated? by'tthe automaticallyreciprocating slide 'of' the .weapon. .This sear tripper has arearwardly extending portion with a sear engagingf foot extendingdownewardly tooverlie the sear, and an upwardly 18X- tending actuatingprojection disposed in the path of .the actuator bar. Another feature ofthemverition resides .in the arrangement of anactuating member connectedby a pivot totheend of the actuator bar and resiliently urged awayfromithe actuating projection on the seartripper. The actuator bar .andactuating member slide" in a1 guidewayformed by a casing attached'tothereceiver bythe same bolt which secures the trigger. housing to thereceiver. #Slidableinthis same casing is a selector having a'cam'forishifting the i actuating member aboutits pivot towardthe ac-"tuating projection on the sear tripper.

Other objects and advantages of thefinvention;

will become apparent from "the following-specification taken inconnection with .the accompanying drawings wherein;

Figure 1 is a vertical sectional view'of' a carbine illustrating apreferred embodiment; of the invention with some parts brokenawayforpurposes of clearness;

Fig. 2 is a top plan view of the carbine with some parts broken :away'and others showni-in section;

Fig. 3 is a side elevation of the carbine with the selector in itsautomatic position; some parts being broken away and others shown in'section;

Fig. 4 is a fragmentary'vertical sectional view of the firing mechanismwithsome parts broken away and others shown-in sectin,'"the'parts beingshown in" positions assumedafter the trigger is pulled and the hammerhas moved to firing position;

Fig. 5 is a vi'ew'similar'toFig. 1- butshowing the slide. and. boltretracted to cock the hammer;

' Fig. 6 'is a view similar to Fig. 4 showing "the parts inv cockedposition with the slide and bolt partially returned to battery position;

Fig; 7 'is a" fragmentary horizontal sectional view of the firingmechanism shown in'Figi 3;

Fig. 8 is a partial top plan'view illustrating the arrangement of theselector;

Fig. 9-is a partial sectionalview taken on the line 9-9 of Fig. 7;

Fig. 10 is a'fragmentary view similar-to'Figi 3,

Fig; 11 is a perspective view or the sear-tripper; and

Fig. 12 is a perspective view ofthe actuatin member on the end of theactuator bar.

A"U. S. carbine, caliber'.3.0M1 has areceiver '2! in the 'forwardend ofwhich a barrel 22 is threaded. Locked by a dovetail joint 23- at therear of the receiverand a transverse bolt 24 at the forward end of thereceiver is a trigger housing 25 arranged below the receiver. Thishousing 25--is formed witha recess 26 in its central portion. -A hammerpin 21, extending across the recess 26, pivotally supports a hammer '28which *moves-in an arcuate path between a cocked position, as shown inFig. 1; and a discharge. or firing position; as shown in Fig. 4. Thishammer 23 hasone side formed with a-recess" 3| (Figs. 2 and 7) extendingbetween its front end 32 and-its rear end 33.

Extending across the recess-2B rearwardlyof hammer pin 27 is a sear pin34. A trigger 35 has a pair of ears =one of-which is illustrated at 36,

extending upwardly through an opening 31 in the bottom of the triggerhousing and pivoted on the sear pin 34. Trigger 35 has a rearwardlyextending portion 38 above which 39. Normally urging the trigger 35 in acounterclockwise direction as viewed in the drawings is a wire spring 40secured to the trigger housing. Arranged between the ears on the triggeris a projects a lip sear 4| formed with an elongated transverse slot 42through which sear pin 34 is inserted permitting pivotal movement of thesear 4| about the pin 34 and longitudinal shifting movement of the searwith respect to the pin. Extending forwardly from the slot 42, sear 4|has a hammer engaging nose 43 arranged to cooperate with notch 44 in thelower part of hammer hammer in cocked position. Trigger engaging seat 45provides a rearward extension on the sear I 4| arranged, when the searis in rearward position as indicated in Fig. l, to rest on lip 39 onthetrigger 35,. and, when the sear is in its forward position as indicatedin Fig. 6, to rest on the upper surface of the rearwardly extendingportion 38 on the trigger. 35. Normally urging sear 4| in a forwardlydirection is a spring 46 retained in a cylindrical recess 4'! formed inportion 38 of the trigger 35 and bearing upon a shoulder 48 extendingdownwardly from seat 45 on the sear The construction thus far describedis the standard design of the U. S. carbine, caliber .30M1. With thehammer cocked, a pull on trigger 35 acts by engagement of lip 39 withseat 45 on the sear to shift nose 43 out of engagement with notch 44 andpermit hammer spring 5| to move the hammer 28 to firing position, as'illustrated in Fig. 4. Then, the explosion of the ammunition producesgases under pressure which act on piston 52 incylinder 53 to move slide54 rearwardly causing bolt 56 to ride over the top part of hammer 28, asillustrated in Fig.5. As the slide 54 and bolt 56 return toward batteryposition, as illustrated in Fig. 6, notch 44 in hammer 28 is engaged bynose 43. If trigger 35 is retained in its pulled position, asillustrated in Fig. 6, seat 45 rests upon the uppersurface of thetrigger portion 38 and bears against the forward end of lip 39 therebyretaining the hammer 28 in cocked position. To again fire the weapon,trigger 35 must be released permitting seat 45 on sear 4| to moverearwardly above the lip 39. Then, a subsequent pull on the trigger willmove the sear in the same fashion as already described.

With a selective fire converter attached to the weapon it may be firedsemi-automatically in the same fashion as the basic weapon, or it may befired automatically in a manner to be described where it will repeat thefiring cycle as long as a pull is exerted on the trigger but will stopfiring immediately upon release of the trigger.

One component of the selective fire converter is a sear tripperdesignated generally at 6| and illustrated in perspective in Fig. 11.This sear tripper 6| has a body portion 62 from which depends an ear 63.A transverse arm 64 extends from the body portion to support anotherdepending ear 65. These car 63 and 65 are arranged in parallel relationand spaced apart a distance corresponding to the outside widths of thetrigger housing at the hammer pin 21. Both ears are provided with alinedholes like the hole 66 in the ear 63 so the sear tripper may bepivotally mounted on the end portions of the hammer pin 21 which projectthrough the walls of the trigger housing. Body 62 of the sear tripper 6|28 to retainthe 1 tion,

has an inwardly offset portion 61 to which is attached a rearwardlyextending arm 68. Thi arm isrelatively thin and generally of arcuateshape lengthwise so it will lie within recess 3| and pergaging foot 69arranged to overlie a raised shoulder or step H on the upper surface ofnose 43 on sear 4|, when the sear is in its forward posias illustratedin Fig. 6. When the sear is in its rearward position, as illustrated inFig. 1, foot 69 is disposed forwardly with respect to step Extendingupwardly from arm 68 is an actuating projection 12 having'at its top acam surface 13 for a purpose to be described. Actuating projection 12 isnormally urged upwardly by a spring 10 connected to the trigger housingand tending to turn the sear tripper in a counterclockwise direction asviewed in the drawings.

Mounted on the side of the receiver 2| is an elongated casing 14 securedby threaded engagement of depending flange 15 with the same bolt 24which connects the trigger housing and the receiver. At its rear end,casing 14 has an inwardly projecting hook shaped lug 16 which engages ina recess 11 at the back of the receiver above dovetail joint 23. Casing14 has a flat exposed side with upper and lower inwardly projectingflanges and 80' forming a guideway along the side of receiver 2|.Slidable in this guideway is an actuator bar 18 having its forward partI9 offset outwardly at 8| and extending beside the path along whichslide 54 reciprocates. At its front end, forward part 19 of bar 18 isturned inwardly to form an abutment 82 which is engaged by forward edge83 of the slide 54. Rearward edge 84 of the slide 54 engages front edge85 of the receiver to arrest rearward movement of the slide. Thisrearward edge 84 of the slide 54 has an undercut edge 86 which engagesan abutment 81 formed on the inner face of actuator bar 18 justrearwardly of offset 8|.

When the slide 54 is in its most forward position, as illustrated inFig. 3, the distance (indicated by dotted line A) from rearward edge 84of the slide to forward edge 85 of the receiver is slightly greater thanthe distance (indicated by dotted line B) from undercut edge 86 on theslide 54 to abutment 81. Upon reciprocation of the slide 54in a rearwarddirection, undercut edge 86 engages abutment 84 to move actuator bar 18a short distance rearwardly from its position, as shown in Fig. 3, tothe position shown in Fig. 5, where rearward edge 84 of the slide 54engages forward edge 85 of the receiver 2|. Then, return of slide 54 toits forward position will reverse the sliding movement of the actuatorbar just as the slide returns the bolt 56 to its battery position, asillustrated in Fig. 7. This limited reciprocating movement of theactuator bar produces a pivotal movement of the sear tripper by means ofthe actuator mechanism now to be described.

As illustrated in Fig. 10, rear end of actuator bar 18 is provided withan inwardly ofiset end portion 9| to which is connected by pivot pin 92an actuating member 94. Actuating mem ber 94 has a horizontal flange 95extending inwardly and rearwardly. At the back of the flange 95 is a cam99 arranged to ride over cam surface 13 on actuating projection 12 ofthe sear tripper when actuator bar 18 is reciprocated by the slide 54.Wire spring I0 I, which is wound e on-'- pivot 92 is: arranged to -actbetween bar n and amember 94 *to resiliently I 'urge actuating member 94*with its: cam 99 about the: pivot "92 away fromactuatingproj ection 2on "the seartrippent I :Forwaidmovement bf theactuator' -..bar -18 islimited by a lug '9 textending inwardly from the bar 18-and'arranged'to-em age .W'all 98 in the receiver.

Slidable atthe rear endof casing ldis a' selector -I02having a bodyportion I03 -slidable in opening IM 'formedin the upper flange B of theca'sing. i1 Forwardly extending fingers I 05 and I BB are sepa- --rateda distaneeequal to the thickness offiange 80 so theyv slidealong theupper and lowersurfaces of the flange. On rearwardly extending portion101 is an operating 1 flange I 08 having a knurled surface accessible*to the thumb of the marksman-so T the selector may 7 be shifted-forwardor backward. A spring 199 e extends rearwar'dly 'mer 128 to again "firetheiweapon andfrepeatithe same- "-cyc-le. This: automatic cyclecontinues. to repeat untillthe trigger -35 is released. Themzas theslide movesactuat-onbar 18 forwardhc'to'gde- 5 press the sear. tripper.::foot i69 :wm :bedepressed -in front of raised step 1 I. because; uponrelease .ofrthe-trigger the sear will move. .to its rearward position;as illustrated'in Fig. .1.

-When semieautom'atic. operation of I the: weapon' is desired, theoperator moves .serratedflange l-fla rearwardly to shift selectoruIIlZ.to. its rear- 1 ward 'or semi-automatic position with detentIIl9engagedin opening H2. 'Ihismovementbf the selector -moves cam surface II 0 out ofz'engage- =ment with cam surface II I soothe; actuatingmember-94': pivots away from the sear :trippen-sso :icam 99 is withdrawnfrom-a position whererzit will-engage cam surface 13 on: the seartripper. A pull on the trigger will cause the gun to "fire vfrom bodyportion 402 and has links arranged 2O-"and the slideand bolt tocock thehammer. .Z-Reto enter openings inxthe fiange'fic- .to serve as a'detentfor the selector. -With the selector I92 in forward-position so detentI09 'is engagedin opening I04, as indicated in Fig. 3, inclined camciprocationof the slide produces reciprocation r of the actuating bar18, but reciprocation of. .the actuating member-Maud the cam99fiisineiiec- .tive' because the camdoes not-engagesthe; actusurfaceIII onthe bottom. of fiangeIiiS engages'25'atingprojection on the seartripper. Hence;:.the

a corresponding camsu'rface' II I von a'ctua ting member 94 to depressthe actuatingmember so-a'ctuating projection 99 will engagecam sur- 1face Won the sear tripper. Whenselector IilZ tweaponwill fire a single.shot and then' remain in cockedpositionauntil the. .triggenis released aandagain pulled.

It will beapparent that-.the...component parts "is shifted to-itsrearward semi-automatic posi-BO: of the selective fire-converter.disclosed: =.herein tion. detent =I 09 engages opening I I2,.asindicated in Fig. 10. In this position inclined-cam surface I I IJ ontheselector is" disengaged from cam-sur- -="-face II I onthe -actuatingmember 94 thereby may be very. easilyzmanufactured. The. actuator bar18: and the actuating .member ey'mayzbe stamped from metal stock.Asimple; rivetzipro- 'vides thepivot 95 connecting these two 1 parts.

permitting spring :Iflttoehift cam 99- u ar'diy e5 Likewise, seartripper EIaandselector lllz may be 1S0 "it-will not-operate the seartripper.

'Wi'th selector I02 in its forward or automatic position; as illustratedin fig 3,-= apull on the -'trigger removes searnose 4|. from-"engagement with the hammer notch 44 so "the' gun will 40 firew'ithefirstround. -Exhau'stgases act-upon piston 52-:which moves slide 54='rea1'wardlyso bolt '56 cocks hammer 28;- as"illu'stratedin'Figf- 5.Asrthe slide approaches itsrearmostpos'ition, undercut edge 8B'engages'rear-.ab'utmentBl on; the actuator bar to reciprocate the bar andactuating member 94 rearwai-dly. Further rearward xmovement= of theslide54, until rearward edge '84 engages forward edge-'85 of the receiver;re-

-*ciprocates theactuator bar 18 rearwardly -andzgg thereby' moves cam'99" rearwardly with respect it to-cam surface 13 on=actuating projection72. This rearmost position'of' rthe :c'am fsa is illus- -trated in Figs.5 andh6, and: in"'dottedlines:in

Fig. 1.

When' the slide-and boltmove-"forwardly to- :wvard battery. position;hammer 28 is retained in cockedposition'by engagement of nosel'43 on thesear. with notch i on the hammeneasillusmade on stamping: machines. Toincorporate this ==selective fire converter in ;.a standardircarbine,itis only-.necessaryirtoreplace'xthe.seaii' in the carbine with .a sear.havingzazraisedstep :II on its hammer engaging nose. '1 Thehammer pinxis removed and an. elongatedhammer pin 21 is insertedwith theseartripperiinzplace. Actuator bar- 18 andselector I82 are-.assembled'incasing T i l-and secured by transverse. screw 24 whiclrreplaces the'pinin; the. standard :carbine. Thus, the component parts are .not onlyeconomically manufactured but may be quickly-assembled-by a soldierin'the field-and very easily maintained.

Whatis claimed ;is: 1.'-An automatic firearm =comprising. .a. re--"ceiVer,-'-a trigger housing'an automatically "reciprocatingslide--onsaid receiver; ahammerr. pin iaextending. through. said housing; ahammer piv- 'otedonrsaid-pin, a-trigger pivotally mountedarin saidhousing".aseaInhaving-an elongated slot;- a pin extending through.saidslct. and mounted :in .::said housing, .arforwardly extendinghammer engaging noseon said sear. arranged. to cooperate with a notch:in: 'sa'id uhammer. and: retaini'said tratedinFig; 6. At-this point,the sear is-Tetfiinedm h m r nr c p r p n win. its forwardposition-byengagement 'of sear -:seat 38-with'lip 39 on thetriggerp-Th-us; the" sear :engaging: foot-'- [i9 on the sear tripperoverlies braised step II on' the sear.

nose, a rearwardly extending" trigger engaging .iseat :on :said searsoverlying said trigger, a scar .xtripper.epivoted on said; hammer. pin,sear engaging foot on: said tripper. overlying saidt-zstep,

As the slide and bolt return tobattery posi-g anupwardlyextending:actuating projectionpn -.-.tion, forward edge 83 on thes slideengagesabutment 82 on the forward end *ofthe actuator bar i to move theactuator bar with actuating member :1942andx cam. 99.? forwardly. lWith:'this. forward z said.seairtripper,v an. actuator bar reciprocablesby.zsaid rslideyand an actuatingsmember-onusaidmar arranged: to:*engageqsaid. projection andy. .move said-.sear'tripp-er in amannercausing saidncse movementr'of theactuating 'member;-.c am; SSi de- 47-tc depressisaid sear.

presses oam surface 13' one-actuating projection I2 against the force ofspring-':'Ifl; thereby pivot- .1 :ing the sear tripper" 6 l aboutthe-hammer pinZI and depressingv foot .69. onto raisedstep :7 lwonithe.ssear and depressing. the sear toreleasethzham+ 2. An 1 automaticlzfirearm comprising a .r're- -:.c'eiver,1.a trigger housing; an.automatically.;:-re-

.=zciprocatingoslide'. on said receiver; a hammertpinextendingxthrouglrsaid housing,ra hammerfpivlmed;onisaidpinpalitriggerspivotally.mcuntedqin said housing, a searhaving an elongated slot, a pin extending through said slot and mountedin said housing, a forwardly extending hammer engaging nose on said seararranged to cooperate with a notch in said hammer hammer in cockedposition, a raised step on said nose, a rearwardly extending triggerengaging seat on said sear overlying said trigger, a sear tripperpivoted on said hammer pin, a sear engaging foot on said tripperoverlying said step, an upwardly extending actuating projection on saidsear tripper, an actuator bar reciprocable by said slide, an actuatingmember on said bar arranged to engage said projection and move said seartripper in a manner causing said nose to.

depress said sear, and a movable selector connected with said actuatingmember for shifting said member relative to said actuating projection.

3. An automatic firearm comprising a-receiver,

an automatically reciprocating slide on said receiver, a hammer pinextending through said housing, a hammer pivoted on said pin, a triggerpivotally mounted in said housing, a sear having an elongated slot, apin extending; through said slot and mounted in said housing, aforwardly extending hammer engaging nose on said sear arranged tocooperate with a notch in said hammer and retain said hammer in cockedposition, a raised step on said nose, a rearwardly extending triggerengaging seat on said sear overlying said trigger, a sear tripperpivoted on said hammer pin, a sear engaging foot on said tripperoverlying said step, an upwardly extending actuating projection on saidsear tripper, an actuator bar reciprocable by said slide, and anactuating member pivotally connected to the end of said bar to engagesaid projection and, move said sear tripper in a manner causing saidnose to depress said sear.

4. An automatic firearm comprising a receiver, a trigger housing, anautomatically reciprocating slide on said receiver, a hammer pinextending through said housing, a hammer pivoted on said pin, a triggerpivotally mounted in said housing, a sear having an elongated slot, apin extending through said slot and mounted in said housing, a forwardlyextending hammer engaging nose on said sear arranged to cooperate with anotch in said hammer and retain said hammer in cocked position, a raisedstep on said nose, a rearwardly extending trigger engaging seat on saidsear overlying said trigger, a sear tripper pivoted on said hammer pin,a sear engaging foot on said tripper overlying said step, an upwardlyextending actuating projection on said sear tripper, an actuator barreciprocable by said slide, an actuating member pivotally connected tothe end of said bar, and a movable selector for shifting said actuatingmember relative to said actuating projection.

5. An automatic firearm comprising a receiver, a trigger housing, a boltsecuring said housing to said receiver, an automatically reciprocatingslide on said receiver, a hammer pivotally mounted in said housing, atrigger pivotally mounted in said housing, a sear having an elongatedslot, a pin extending through said slot and mounted in said housing, aforwardly extending hammer engaging nose on said sear arranged tocooperate with a notch in said hammer, a raised step on said nose, arearwardly extending trigger engaging seat on said sear overlying saidtrigger, a sear tripper pivotally mounted on the pin for said hammer. asear engaging foot on a trigger housing,

and retain said said tripper overlying said step, an upwardly extendingactuating projection on said sear tripper, a casing extending along theside of said receiver and secured thereto by said bolt, an actuator barslidable in said casing and reciprocable by said slide, and an actuatingmember pivotally connected to said bar and arranged to engage gatedslot, a pin extending through, said slot 7 and mounted in said housing,a forwardly extending hammer engaging nose on said sear arranged tocooperate with a notch in said hammer, a raised step on said nose, arearwardly extending trigger engaging seat on said sear overlying saidtrigger, a scar tripper pivotally mounted on the pin for said hammer, asear engaging foot on said tripper overlying said step, an upwardlyextending actuating projection on said sear tripper, a casing extendingalong the side of said receiver and secured thereto by said bolt, anactuator bar in said casing reciprocable by said slide, an actuatingmember pivotally connected to said bar, and a selector member mounted onsaid casing for shifting said actuating member relative to saidactuating projection.

7 An automatic firearm comprising a receiver, a trigger housing, a boltsecuring said housing to said receiver, an automatically reciprocatingslide on said receiver, a hammer pivotally mounted in said housing, atrigger pivotally mounted in said housing, a sear having an elongatedslot, 3, pin extending through said slot and mounted in said housing, aforwardly extending hammer engaging nose on said sear arranged tocooperate with a notch in said hammer, a raised 'step on said nose, arearwardly extending trigger engaging seat on said sear overlying saidtrigger, a sear tripper pivotally mounted on the pin for said hammer, asear engaging foot on said tripper overlying said step, an upwardlyextending actuating projection on said sear tripper, a casing extendingalong the side of said receiver and secured thereto by said bolt, anactuator bar slidable in said casing, spaced abutments on the forwardend of said bar engageable by said slide to reciprocate said bar, and anactuating member on said bar arranged to engage said actuatingprojection.

8. In an automatic firearm having a hammer pivotally mounted on a hammerpin, a scar for engaging a notch in said hammer, and an automaticallyreciprocating slide for cooking said hammer, a selective fire convertercomprising a sear tripper pivotally mounted on said hammer pin, a seardepressing foot on said sear tripper overlying said sear, an actuatingprojection on said sear tripper, an actuator bar reciprocated by saidslide, and an actuating member on said bar arranged to engage saidactuating projection upon reciprocation of said bar.

9. In an automatic firearm having a hammer pivotally mounted on a-hammerpin, a sear for engaging a notch in said hammer, and an automaticallyreciprocating slide for cocking said hammer, a selective fire convertercomprising a sear tripper pivotally mounted on said hammer pin, a seardepressing foot on said sear tripper overlying said sear, an actuatingprojection on 9 said sear tripper, an actuator bar reciprocated by saidslide, an actuating member pivoted on said bar, and a movable selectorconnected to said member for shifting said member relative toprojection.

10. In an automatic firearm having a hammer pivotally mounted on ahammer pin, a sear for engaging a notch in said hammer, and anautomatically reciprocating slide for cooking said hammer, a selectivefire converter comprising a sear tripper pivotally mounted on saidhammer pin, a sear depressing foot on said sear tripper overlying saidsear, an actuating projection on said sear tripper, an actuator barreciprocated by said slide, an actuating member pivotally connected tothe end of said bar, spring means resiliently urging said member from aposition to engage said projection upon reciprocation of said bar, and amovable selector connected to said member for shifting said memberagainst said spring means to a position to engage said projection.

11. In an automatic firearm having a hammer pivotally mounted on ahammer pin, a scar for engaging a notch in said hammer and anautomatically reciprocating slide for cooking said hammer, a selectivefire converter comprising a sear tripper pivotally mounted on saidhammer pin, a real-wardly projecting arm on said sear tripper, a seardepressing foot extending downwardly from said arm to overlie said sear,an actuating projection extending upwardly from said arm, an actuatorbar reciprocated by said slide, and an actuating member on said bararranged to engage said projection and move said sear tripper to depresssaid sear.

12. In an automatic firearm having a hammer pivotally mounted on ahammer pin, a scar having an elongated slot permitting longitudinalshifting of said sear on a pin through said slot, a raised step on thehammer engaging nose of said sear, and an automatically reciprocatedslide for cooking said hammer, a selective fire converter comprising asear tripper pivotally mounted on said hammer pin, a rearwardlyprojecting armon said sear tripper, a sear depressing foot extendingdownwardly from said arm and overlying said step only when said sear isshifted forwardly, an actuating projection extending upwardly from saidarm, an actuator bar reciprocated by said slide, and an actuating memberon said bar arranged to engage said projection upon reciprocation ofsaid bar.

13. In a selective fire converter for an automatic fire arm having atrigger housing, a hammer pivotally mounted therein, a sear for engagingsaid hammer, an automatically reciprocated slide for cooking saidhammer, and an actuator bar .reciprocated by said slide; a sear trippercomprising a body, a first ear depending from said body, a transverselyextending portion on said body, a second car depending from said portionparallel to said first ear and spaced therefrom a distance correspondingto the outside width of the trigger housing, said ears being formed withalined holes to mount said sear tripper on the pivot pin for saidhammer, a rearwardly extending arm on said body, a sear engaging footextending downwardly from said arm, and an actuating projectionextending upwardly from said arm to be engaged by said actuator bar.

14. In a selective fire converter for an automatic fire arm havingatrigger housing, a hammer pivotally mounted therein, the hammer beingformed with a longitudinally extending recess in one side, a sear forengaging said hammer, an automatically reciprocating slide for cookingsaid hammer, and an actuator bar reciprocated by said slide; a seartripper comprising a body, a first ear depending from said body, asecond ear depending from a transversely extending portion of said bodyparallel to and spaced from said first car a distance corresponding tothe outside width of the trigger housing, said ears being formed withalined holes to mount said sear tripper on the pivot pin for saidhammer, an arcuately shaped rearwardly extending arm inwardly offsetfrom said first ear to lie within the recess in said hammer and permitrelative movement of said sear tripper and said hammer on the pivot pinfor said hammer, a sear engaging nose depending from said arm, and anactuating projection extending upwardly from said arm into the path ofsaid actuator bar.

15. In a selective fire converter for an automatic firearm having apivotally mounted ham;

mer, a sear for engaging said hammer. an automatically reciprocatingslide for cooking said hammer and a pivotally mounted sear tripper fordepressing said sear; actuator mechanism comprising a longitudinallyextending casing, an actuator bar slidably mounted in said casing alongthe path of said slide, spaced abutments on said actuator bar engageableby said slide to reciprocate said bar, an actuating member pivoted tothe rear end of said actuator bar, spring means resiliently urging saidmember away from said sear tripper, and a selector slidable on saidcasing to move said member toward said sear tripper against the force ofsaid spring.

16. In a selective fire converter for automatic firearms, actuatormechanism as defined in claim 15 wherein said selector has a camengageable with said actuating member to move said member about saidpivot against the action of said spring means.

ALONZO F. GAIDOS.

No references cited.

